Complement plays an essential role in shock following intestinal ischaemia in rats.

Intestinal ischaemia lasting more than 30 min in rats causes fatal systemic shock. Systemic shock was suppressed by preadministration of cobra venom factor (CVF), which reduced the serum complement to less than 5% of the normal level, indicating that complement is involved in the syndrome. After complement activation, anaphylatoxins such as C3a and C5a are generated, and their activity is restricted by carboxypeptidases which remove C-terminal arginine from such bioactive peptides. As expected, preadministration of a carboxypeptidase inhibitor enhanced the systemic shock induced by the intestinal ischaemia. However, when the complement level was suppressed by CVF treatment, no fatal systemic shock was induced by the intestinal ischaemia even with preadministration of the carboxypeptidase inhibitor. These results indicate that complement plays a crucial role in systemic shock induced by intestinal ischaemia, and that anaphylatoxins generated by the complement activation should be involved in induction of the shock syndrome.